Spray mist instead of air conditioning: water atomizer for the terrace and garden

Heat wave on the balcony and terrace? Inexpensive spray mister systems use a fine water mist to provide noticeable cooling – without increasing your electricity bill.

If the current Heat wave When temperatures rise well above 30 degrees Celsius, the balcony and terrace quickly become a heat trap. Parasols and awnings provide shade, but they hardly lower the ambient temperature. Fans increase power consumption and mobile air conditioning units are unsuitable for outdoor use.

One cheap and energy-saving alternative are Spray mister systems. Fine nozzles atomize tap water into a mist that evaporates in the warm air and removes heat. The so-called adiabatic cooling reduces the perceived temperature by several degrees – without chemicals and with minimal water consumption of around 13 liters per hour.

The guide explains how Mist cooling technically works, how much water and pressure are necessary and where the systems are used sensibly. In the practical test, inexpensive no-name sets from eBay and Amazon starting at 20 euros compete against the spray mist set from Gardena. A look at purchasing criteria, prices and use as automatic plant watering rounds off the article.

The principle of the water atomizer is simple: water is pressed through fine nozzles at high pressure, creating a very fine water mist. Ideally, the drops are so small that they do not even reach the ground, but are converted into vapor by the sun beforehand. This evaporation removes energy from the environment in the form of heat.

The cooled air sinks downwards and mixes with the warmer air on the ground – this reduces the temperatures in the occupied area. Massive fluctuations are not to be expected, but there is a difference of a few degrees. Added to this is the pleasantly cooling effect of the fine mist on the skin.

In addition to the nozzles, the fineness of the water drops depends on the water pressure. The higher the pressure, the finer the water can be distributed. In a normal household the pressure is in the single digits, in Munich it fluctuates between 3 bar and 7 bar, although it is more towards 3 bar. Commercial systems for catering or indoor humidification use separate pumps to increase the pressure to 40 bar or more.

In addition to the pressure, the ambient temperature is important. The hotter it is, the better the mist evaporates and the better it feels. In practical tests, the systems performed significantly better as soon as temperatures climbed above 30 degrees.

Thanks to the narrow nozzles, the system’s consumption is significantly less than what a lawn sprinkler produces. Gardena specifies a flow rate of 13 l/h for its spray mister. Our other kits we tried are likely to be in a similar category.

For comparison: a classic lawn sprinkler consumes between 600 and 800 l/h, depending on the water pressure. This not only makes the spray misters a good alternative for cooling the terrace, but is also worthwhile for selective watering of garden plants – although there are also alternative irrigation hoses with holes or dedicated micro-drip systems. We show you more about this in our guide to automatic irrigation for the living room, balcony and terrace.

The first fogger in the test is a close one 31 Euro expensive Offer from eBay. These systems are available there under a variety of names between 20 euros and 60 euros. But the structure is roughly the same: several mist nozzles are connected to a standard PU hose, at the end of which there is a screw connection for the tap. The 6 × 4 mm PU hoses used are inexpensive, so you can easily extend the range.

The construction is very simple: The nozzles are hung on beams or a line using the cable ties provided, then the connection to the faucet is tightened. Turn on the water and the foggers start. In practice, there are a few problems: The seal on the faucet was poor underground in our test kit, and more water sprayed out there than from the nozzles. This can be easily remedied with two or three additional sealing rings.

Problem number two is the alignment of the nozzles. Ideally, they should spray upwards at a height of 200 to 250 cm to ensure the highest possible evaporation. But since you can no longer align them after lashing them with cable ties, you have to work cleanly from the start. If you don’t have suitable places to tie things down, you have to work very carefully. Otherwise, adhesive mounts will come loose at high temperatures or moisture.

The third and biggest problem is the cheap nozzles themselves: after a few days of operation, the first few of them were clogged. Even if the replacement is easy, the cable ties require more effort.

Test conclusion: The foggers are a quick and inexpensive solution if you want to do a little tinkering. The cable ties in the inexpensive sets are a comfortable hanging system until you have to replace the nozzle.

The water mist is not so fine that you would want to work with an electronic device underneath it, but it feels very good, especially in hot weather. If you install the nozzles a few meters apart, you will stay dry when there is no wind – the temperature inside the water mist wall will still drop noticeably.

An excellent alternative application is to directly sprinkle balcony or vegetable plants in pots or raised beds. The system can be easily expanded thanks to the standard components.

This is test subject number two city gardening Outdoor Sprühnebel Automatic Set from Gardena. For just under 63 Euro You get seven nozzles, a 10 m long hose, ten hanging loops for fabric or wood and a manual irrigation control. Alternatively, there is a set without irrigation control, which is significantly cheaper.

If you already have a Gardena-compatible connection, simply plug in the fogger system and get started. All others need a corresponding tap connector. One nozzle is pre-installed, the others can be connected by cutting the hose, putting it on the nozzles and tightening the locking ring.

In addition to the fine water distribution, we liked two things: The hanging system for the hose is a simple loop with a clamp. This makes it easy to attach the water mister to umbrellas or to the top of a trampoline. You can also change the position of the nozzles after hanging and align them perfectly.

The nozzles deliver a very fine mist, but it probably still arrives at the ground as water due to the line pressure. In some cases, larger drops also form – this may also be due to the line pressure being too low.

Test conclusion: With its spray mist set, Gardena provides an easy-to-use complete solution whose hanging system and spray mister are pleasantly well thought out. The nozzles didn’t get clogged in the test, but the water mist isn’t fine enough to work with a laptop underneath. If you don’t want to spend a long time tinkering and already have a Gardena-compatible water connection, you can use it without hesitation. What we liked in the test was that the system was easy to convert.

Many of the no-name offers on eBay and Amazon are only available for a short time or in small quantities, which is why the products cannot be found in our price comparison. After all, the availability of products on Amazon and eBay has improved significantly since the last version of this article.

If you are looking for offers yourself, you should take some time and compare the prices. Important: When buying on platforms like Amazon, eBay or Aliexpress, pay attention to the delivery time! Currently, many products are not immediately available and, in the worst case, will not arrive until the end of summer.

Hoses, cable ties and replacement nozzles are also included in most sets, but we recommend purchasing an additional one 2 or 4 way distributor for convenient switching between nebulizer and garden hose.

Thanks to their low water consumption, the foggers are ideal for targeted watering of balcony or potted plants. You can use the cheap spray misters for this, but the droplet size doesn’t matter. It is easy to align the water misters in flower boxes and water the plants in a targeted manner.

Once set up, these computers take care of the irrigation. For the test, we connected the analog water meter included with the Gardena set to the nozzles from the eBay set.

The idea: The system should water the flower boxes for five minutes every few hours, even when you are away. Basically it worked great. Once programmed, the system starts reliably, opens the valves and lets the nozzles distribute the water. This can be used to reliably supply plant troughs with water. If you have a smart system, you can even go one step further and automatically control the irrigation times depending on the temperature. More about this in our article Dumb vs. smart: Who needs which irrigation system?

However, we would advise against using the computers for automatic cooling. As mentioned above, the drops are not so fine that they evaporate completely before they hit the ground. In other words, anyone who sits under the fog with a laptop or a book will get more moisture than they would like. Here we recommend switching on the water misters manually and first clearing the area of ​​products that do not tolerate water. Of course, there’s nothing wrong with using a smart irrigation computer that you activate via a smartphone app or Alexa call.

With a comparatively small investment of 20 to 30 euros, you can set up a reasonable mister system in the garden, on the balcony or on the terrace. This doesn’t keep up with the solutions in the catering industry, but it creates a much more pleasant climate and is refreshing just from the fine water mist. Regardless of whether it’s Gardena or the cheap no-name alternative, both deliver a usable mist, depending on the line pressure.

The acceptable water consumption makes the water misters interesting not only for cooling sunbathers. The systems are so flexible that it is comparatively easy to implement targeted watering of plants in pots or flower boxes.

Coupled with (smart) automatic watering, you can water your own flowers and herbs much more effectively than if you go over them with a jug once a day.

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